1. Field of the Invention
The present invention relates to an optical image capturing lens assembly, and more particularly to a compact optical image capturing lens assembly applicable to electronic products as well as the extended usage in the three-dimensional imaging lens assembly.
2. Description of the Prior Art
In recent years, with the popularity of compact photographing lens assembly, the demand for compact image capturing modules is increasing, and the sensor of general photographing lens assembly is none other than CCD (Charge Coupled Device) or CMOS Sensor (Complementary Metal Oxide Semiconductor Sensor). Furthermore, as advances in semiconductor manufacturing technology have allowed the pixel size of sensors to be reduced and electronic products have become more compact and powerful, there is an increasing demand for compact photographing lens assembly featuring better image quality.
Generally, a conventional compact photographing lens assembly for portable electronic devices, such as the one disclosed in U.S. Pat. No. 7,184,225, is of a triplet type comprising, in order from the object side to the image side: a first lens element with positive refractive power; a second lens element with positive refractive power; and a third lens element with negative refractive power.
With advances in semiconductor manufacturing technology and current trend of compact electronic products, the three-element lens has become insufficient for a high-end photographing optical system due to the increasing demand for a higher image quality.
A conventional high-resolution photographing lens assembly, such as the one set forth in U.S. Pat. No. 7,365,920, generally has a front stop and four lens elements, wherein two spherical-surface glass lenses serving as the first and second lens elements are adhered together to form a doublet for correcting the chromatic aberration. Such an arrangement of optical elements, however, has the following disadvantages: (1) the degree of freedom of the system is curtailed due to the employment of excess number of spherical-surface lenses, thus the total track length of the system cannot be reduced easily; (2) the process of adhering glass lenses together is complicated, posing difficulties in manufacturing. Moreover, as the size of the image capturing lens assembly is becoming smaller and the specification thereof is becoming higher, assembling lens elements tightly within a limited space predisposes unwanted light rays to be reflected for many times within a lens barrel, which will affect image quality. Thus, the unwanted light rays should be prevented from entering the image forming area so as to improve image quality. Inasmuch as the foregoing, a need exists in the art for a photographing optical system that features better image quality and a moderate total track length and is applicable to compact portable electronic devices.